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Concern for engine particle emission led to EC regulations of the number of solid particles emitted by LDV and HDV. However, all conventional piston-driven combustion engines emit metal oxide particles of which only little is known. The main sources are abrasion between piston ring and cylinder, abrasion of bearing, cams and valves, catalyst coatings, metal-organic lubrication oil additives, and fuel additives. While abrasion usually generates particles in the μm range, high concentrations of nanosize metal oxide particles are also observed, probably resulting from nucleation processes during combustion. In general, metal oxides, especially from transition metals, have high surface reactivity and can therefore be very toxic, especially nanosize particles, which evidently provide a high specific bioactive surface and are suspected to penetrate into the organism. Hence, these particles must be scrutinized for quantity, size distribution and composition.

The objectives of the present work are to investigate the regulated and unregulated (particle) emissions of a classical and modern 2-stroke and a typical 4-stroke scooter with different ethanol blend fuels. There is also comparison of two different ethanol fuels: pure ethanol (E) *) and hydrous ethanol (EH) which contains 3.9% water and is denatured with 1.5% gasoline. Special attention is paid in this research to the hydrous ethanol, since the production costs of hydrous ethanol are much less than those for (dry) ethanol. The vehicles are with carburettor and without catalyst, which represents the most frequent technology in Eastern Asia and offers the information of engine-out emissions. Exhaust emissions measurements have been performed with fuels containing ethanol (E), or hydrous ethanol (EH) in the portion of 5, 10, 15 and 20% by volume. During the test systematical analysis of particle mass (PM) and nano-particles counts (NP) were carried out.

Advances in emission control technologies have demanded development of new ceramic chemistries and improved microstructures in catalytic substrates and especially in diesel particulate filters. High porosity filters are desirable, as they decrease engine backpressure and enable application of advanced catalysts including, but not limited to, multi-functional filters (MFF). A significant recent development has been in the use of ceramic fibers to create cross-linked microstructures in extruded honeycomb ceramics. This development allows high porosities to be attained while maintaining mechanical strength. However, according to the World Health Organization, certain classes of ceramic fibers are considered to have adverse health effects if released in air and inhaled.

2- and 3-wheelers with 2-S propulsion are still a very serious source of air pollution worldwide in many urban areas. Therefore, every effort to reduce the emissions of those vehicles is an important contribution to improve the air quality. In the present work detailed investigations of regulated emissions and of particle emissions of 2-stroke scooters with direct injection and with carburator were performed. To demonstrate the emission reduction potentials some possibilities of emission improvements were grouped into steps. These technical measures were: ○ Higher tier lube oils ○ Lower oil dosing ○ Active oxidation catalyst ○ Supplementary filtration & oxidation devise (WFC) **) ○ Special fuel. Particle mass and nanoparticles (number), which are amply present in 2-stroke exhaust gas and which contribute strongly to the toxicity level are still unlimited by the international exhaust gas legislation. They were extensively investigated in the present project series.

General Motors' 3.6L DOHC 4V V6 engine has been upgraded to provide substantial improvements in performance, fuel economy, and emissions for the 2008 model year Cadillac CTS and STS. The fundamental change was a switch from traditional manifold-port fuel injection (MPFI) to spark ignition direct injection (SIDI). Additional modifications include enhanced cylinder head and intake manifold air flow capacities, optimized camshaft profiles, and increased compression ratio. The SIDI fuel system presented the greatest opportunities for system development and optimization in order to maximize improvements in performance, fuel economy, and emissions. In particular, the injector flow rate, orifice geometry, and spray pattern were selected to provide the optimum balance of high power and torque, low fuel consumption, stable combustion, low smoke emissions, and robust tolerance to injector plugging.

An active oxidation catalyst is an efficient measure to reduce not only gaseous components (CO, HC), but also particle emissions (mostly oil condensates) of a small 2-stroke engine with lost oil lubrication. Since the 2- and 3-wheelers with 2-stroke propulsion are still a very serious source of air pollution worldwide in many urban areas, it is important to have a look on some consequences of an improperly working catalyst. The present paper shows some results of user-oriented aging of catalyst on the vehicle and results of limited emissions and unlimited (nano)particles during the catalysts screening tests. The works are a part of an international scooter network project, which was performed (2004 to 2007) in the Laboratories for IC-Engines & Exhaust Emission Control of the University of Applied Sciences, Biel, Switzerland with main support of the Swiss Federal Office of Environment (BAFU), Swiss Petrol Union (EV) and Swiss Lubes (VSS).

During the VERT *) testing of different DPF systems it was remarked, that the oxidation catalyst converts sometimes a big part of NO to NO2, producing on the one hand a more toxic composition of the exhaust gases and causing on the other hand measuring artefacts, which tend to underestimate of NO2 and NOx by the cold NOx - measurement. The present work summarizes the experiences in this matter elaborated at the Laboratories for IC-Engines & Exhaust Emissions Control (AFHB) of the University of Applied Sciences Biel-Bienne, Switzerland, during several VERT activities and didactic projects on engine and chassis dynamometers in the years 2000-2006.

Limited and non-regulated emissions of scooters were analysed during several annual research programs of the Swiss Federal Office of Environment (BAFU) *). Small scooters, which are very much used in the congested centers of several cities, are a remarkable source of air pollution. Therefore every effort to reduce the emissions is an important contribution to improve the air quality in urban centers. In the present work detailed investigations of particle emissions of different 2-stroke scooters with direct injection and with carburettor were performed. The nanoparticulate emissions were measured by means of SMPS, (CPC) and NanoMet. Also the particle mass emission (PM) was measured with the same method as for Diesel engines. Extensive analyses of PM-residuum for SOF/INSOF, PAH and toxicity equivalence (TEQ), were carried out in an international project network. Particle mass emission (PM) of 2-S Scooters consists mostly of SOF.

The development of engines with high specific output and low specific fuel consumption is now more than ever becoming the main focus for powertrain product development. A combination of two primary factors is driving this demand: increased fuel cost and stricter government regulations. As worldwide fuel prices continue to increase, consumers are shifting their purchasing toward more fuel-efficient vehicles. Also fueling the demand is new federal corporate average fuel economy (CAFÉ) regulations that are in place for the timeframe from 2008 to 2011. One concept to provide both high specific output and low specific fuel consumption is the combination of turbocharging and gasoline direct fuel injection. This is an attractive concept for the North American market where sport utility vehicles, light trucks and sports cars of all sizes are in demand from consumers.

Limited and nonlimited emissions of scooters were analysed during several annual research programs of the Swiss Agency of Environment Forests and Landscape (SAEFL, BUWAL)*). Small scooters, which are very much used in the congested centers of several cities are a remarkable source of air pollution. Therefore every effort to reduce the emissions is an important contribution to improve the air quality in urban centers. In the present work detailed investigations of particle emissions of different 2-stroke scooters with direct injection and with carburetor were performed. The nanoparticulate emissions with different lube oils and fuels were measured by means of SMPS, (CPC) and NanoMet *). Also the particle mass emission (PM) was measured with the same method as for Diesel engines. Extensive analyses of PM-residuum for PAH & SOF/INSOF, as well as for VOC were carried out in an international project network.

Gasoline Direct Injection (GDI) engines can play an important role in future powertrain concepts. They show potential for enhanced fuel economy and at the same time fulfill demands for higher specific power output. For a successful placement in the NAFTA market especially against other competing concepts such as the gasoline port fuel injection engine and the Diesel engine, GDI has to demonstrate its ability to meet existing and future emission legislation. This contribution demonstrates GDI as a low emission concept. It proposes a reliable and efficient cold-start strategy called “High-Pressure Stratified Start”. Fuel is injected by means of increased fuel pressure during compression stroke instead of the conventional start with low-pressure fuel injection during intake stroke. Consequently, mixture preparation is greatly enhanced and wall wetting is reduced. The high-pressure start produces less unburned hydrocarbon emissions and enhances start reliability at low temperatures.

The goal of the Clean Engine Vehicle project (CEV) was the conversion of a gasoline engine to dedicated natural gas operation in order to achieve a significant reduction in CO2 emissions. The targeted reduction was 30% compared with a gasoline vehicle with similar performance. Along with the reduction in emissions, the second major requirement of the project, however, was compliance of the results with Euro-4 and SULEV emission limits. The project entailed modifications to the engine and the pre-existing model-based engine control system, the introduction of an enhanced catalytic converter and downsizing and turbocharging of the engine. As required by the initiators of the project, all components used were commonly available, some of them just being optimized or modified for natural gas operation.

Different Diesel Particle Filters (DPF)*) were tested on a 2-Stroke Detroit-Diesel bus engine 6V 92 TA. The investigations focused on soot burden and regeneration of the DPF with special filter materials. Also examined was promoting the regeneration by: throttling, additive (FBC), oxidation catalytic converter upstream of DPF and the catalytic coating of the filter material. The metrics were the particulate matter emission, its composition and the nanoparticles. The most important results are: The average SOF content in the engine exhaust particulate matter is 77.6 % and the majority of it is emitted as bigger droplets The wire-mesh filter catalyst (WFC) - a novel emission reduction technology -substantially curtails the SOF and PM. WFC traps and oxidizes the oil droplets and produces a “dry” soot. This can be very advantageous for the DPF downstream of WFC. (WFC can be also very interesting for 2-S gasoline engines).

In order to meet future requirements for emission reduction and fuel economy a variety of concepts are available for gasoline engines. In the recent past new pathways have been found using alternative fuels and fuel combinations to establish cost optimized solutions. The presented concept for a SI-engine consists of combined injection of gasoline and hydrogen. A hydrogen enriched gas mixture is being injected additionally to gasoline into the engine manifold. The gas composition represents the output of an onboard gasoline reformer. The simulations and measurements show substantial benefits to improve the combustion process resulting in reduced cold start and warm up emissions and optimized part load operation. The replacement of gasoline by hydrogen-rich gas during engine start leads to zero hydrocarbons in the exhaust gas.

1 In the present work investigations of a 7.8 liter-TC-IC-IVECO-CNG engine were performed with single point (SPI) *) and with multipoint (MPI) gas injection systems. Three types of MPI injectors available on the market were compared for stationary and transient engine operation. There are several advantages of MPI e.g. better possibility to equalize the air-fuel-ratio of the cylinders, optimization of the gas injection timing and of the gas pressure for different operating conditions. With different injector types there are different optimum injection timings, due to different injection durations, but at the optimum conditions there is little difference in the combustion quality. The injectors with higher flow rate can cause more λ-excursions in the dynamic response and with sudden changes of the gas pressure.

1 The topic of investigation of this work was the influence of different gas qualities on the engine parameters and particularly on the air excess factor λ. For this research the normalized gases with extreme compositions were used. At stationary operation there are no differences of the leaning capability of the different gases. The gas with the highest content of inert components causes the lowest full load power, the highest fuel consumption and the highest cyclic irregularity. With the same air flow and the same injection duration for different gases result different air excess factors λ according to the density and to the necessary stoichiometric air quantity of each gas. This fact influences the λ at transient operation conditions as: cold starting, gas quality jump, or load increase, if there is no λ-control. With an active λ-control, which is today fast enough, especially with an adaptive system there are no problems with λ- differences.

By the intense inflammation and high combustion rates in the spark ignition engine oscillatory combustion is formed, similarly to the diesel engine. The oscillation is particularly marked in the engines with divided combustion chamber, due to the rapid combustion caused by the turbulence generated in the prechamber nozzles. Oscillatory combustion and knocking are two different phenomena with different causes. It will be tried in this paper to clarify the reasons of formation of pulsating combustion and the parameters which influence it. Also the differences between the oscillatory combustion and knocking in the gasoline engines and the influence of turbulence on knocking will be shown.